Converting from Gas Boiler to Heat Pump

Why switch to a heat pump? Here are key considerations and steps for those contemplating the transition from a traditional gas boiler to a more sustainable heat pump system:

Hydronic System Compatibility

Ensure that your existing hydronic heating system is compatible with the heat pump. While most hydronic systems can work with a heat pump, some modifications may be needed to optimize performance.

It is not always economically viable to swap from gas boilers to heat pumps, to assist with this assessment you could complete the online table below, which would give a good indication. This does not consider the altruistic aspect of moving away from gas, a non-renewable resource.

If you have in-slab hydronic heating, in all likelihood it is a good alternative to the gas boiler.

Radiators

Radiators are harder to justify for a heat pump conversion due to the water temperatures being far hotter at around 70 – 80 degrees than in slab at 40 degrees, as heat pumps struggle with higher temperatures, for new homes see Radiators and Heat pumps.

However, if the radiators are oversized, maybe adding a few additional radiators and or the house is well-insulated, it’s still possible to install a heat pump, as we have done on many occasions.

Insulation and Efficiency Improvements

Consider improving insulation and air sealing in your home to reduce heating demand and maximize the efficiency of the heat pump.

Calculating gas usage

To consider converting from a gas boiler to a heat pump, you need to check the gas consumption for the last few years if possible, and remove non-heating gas usages, like hot water and cooking by looking at the summer usage.

This is the best method to determine heating requirements, rather than using just general assumptions. With this information:

• We can calculate heat pump sizing and
• Some running costs as a starting point.
• Identifying very quickly if it’s economically viable.

If occupancy is very low then current gas consumption may not be an accurate guide for estimating heating requirements.

Downsides to Consider with Heat Pumps

• The heat pump’s initial cost is usually at least double the cost of a gas boiler.
• Performance in colder climates, needing a larger size to accommodate the loss of output at zero or lower temperatures.
• Noise is also a consideration, placed away from bedrooms, although they have improved tremendously and most clients do not notice the noise at night.
• Sizing, they are not small and need to be placed outside with good ventilation all around.